1. Field of the Invention
This invention relates to pharmaceutical container closures, and in particular to a calendaring cap for a pharmaceutical container.
2. Background of the Invention
Advances in medicine have made possible the accurate prescription of ethical pharmaceutical drugs to treat a wide variety of afflictions. Typically these pharmaceutical drugs must be ingested orally a number of times daily, every day of the week. It is not unusual for one individual to be taking several different drugs at one time.
Most of these drugs are self-administered--that is, the patient is responsible to for keeping track of what has been ingested, and when to ingest the next dose, of each drug. A major problem associated with this self-medication is the danger that the wrong dosage will be administered. This generally occurs where a patient forgets whether, and when, the previous dose was administered, and either duplicates a dose or skips a dose. Over time, such drug mis-administration detracts from the efficacy of the drug, and can even be life-threatening where the drug is dangerous in overdose, or where minimum doses are required for health reasons.
This problem becomes even worse where a patient's mental faculties have become impaired due to advanced years, the dulling effect of the selfsame drugs prescribed, or disease. Where the patient's memory is not very good, it is easy for the patient to forget whether the previous dose was administered, and thus the chances of mis-administration increase.
Where the patient is self-administering a number of different drugs (four or five different drugs is not uncommon) the problem may become especially severe--the patient may recall having self-administered one drug, when in fact a different drug was taken. This patient mis-perception can lead to overdose of some drugs, and underdosage of others. Thus the challenge becomes one of keeping track of when the last dose of a specific medication was self-administered.
Existing Designs
A number of designs have been suggested to remind the patient when the last dose of a given drug was self-administered. U.S. Pat. No. 5,482,163 was granted Hoffman for a Last Event Indicator, which featured a rotating ring around a pill bottle. The patient rotated the ring to indicate what day of the week and dose number was last self-administered. There were a number of problems associated with this design. First, the patent taught an entire bottle had to be manufactured with a rotating ring around it. This idea was relatively expensive because the entire bottle had to be changed from a standard pill bottle. In addition, only one ring was taught, which made it difficult to precisely specify which dose was last taken where several doses per day were required.
Several inventions featuring indicating means built into a bottle cap have been patented. Rollman and Leopoldi et al. were granted U.S. Pat. Nos. 5,011,032 and 3,684,117 respectively for rotating bottle caps which incorporated windows through which underlying indicia could be observed. These designs both required that an aperture (window) be formed through the cap which would provide an optical pathway through the cap. The Leopoldi et al. '117 patent was in fact for a type of combination lock-cap, not for a calendaring cap.
Mehaffey was granted U.S. Pat. No. 2,111,637 for a Bottle Cap With Indicating Means. This patent taught a ring rotating on a cap, which was attached to the cap by means of a washer and screw. This design suffered from the drawbacks of complexity and thus expense. In addition, the danger existed that the screw might unscrew itself over time, and the ring fall off, thereby erasing the record of the day and time when the previous dose was taken.
Several patents have been granted for caps which rotated relative to containers on which they were installed. North and Babbitt, III were granted U.S. Pat. Nos. 2,706,464 and 3,766,882 respectively for dose time indicating containers. Both provided a cap which rotated relative to a container upon which the cap was installed. One provided an pointer on the cap and time indicia inscribed on the container; the other provided an pointer on the container and time indicia inscribed on the cap. Both these designs relied on a frictional fit between the cap and the container for the designs to work.
There were a number of drawbacks associated with these designs. First, modem drug bottles incorporate childproof rotating caps, and these designs are incompatible with such childproof caps. Second, many modem pill bottles incorporate screw-on caps. The North and Bobbitt, III designs would not work with screw-on caps, because the rotational orientation of a screw cap relative to a container is determined by the length of the thread. Finally, because the North and Bobbitt, III caps are removed and replaced with every dose of medicine taken, the frictional fit between the cap and bottle might become loose over time. If the cap/bottle fit were to become too loose, the cap would not remain in the same rotational position relative to the bottle, thus rendering its indication unreliable.